Continuous dyeing of vegetable fibres



United States P3116111:

CONTINUOUS DYEING 0F VEGETABLE FIBRES WITH VAT DYES Robert S. E. Hannay, Darnick, Melrose, and William Kilby, Eden Park, Lancaster, England, assignors to Standfast Dyers & Printers Limited No Drawing. Application April 4, 1955 Serial No. 499,243

Claims priority, application Great Britain April 8, 1954 9 Claims. (Cl. 8-34) This invention relates to the continuous dyeing with vat dyes of cotton, linen or other vegetable fibres which latter term is to be taken as embracing the fibres whether in the form of fabrics, yarns, filaments or the like.

The term continuous dyeing is intended to refer to that class of dyeing in which the material to be dyed is continuously passed into, through, and out of an aqueous dyebath, as distinct from batch dyeing in which the material is dyed in batches which are intermittently inserted and taken out of the dyebath.

It has been known to dye yarns or fabrics continuously with vat dyes, using aqueous dye liquors containing caustic alkali and sodium hydrosulphite. The alkali strength of such dye liquors is determined by the quantity of dyestutf and hydrosulphite used, but does not normally exceed 60 grammes per litre.

We have found as a result of experiment that considerable economy in dyestufi cost can be attained in said continuous dyeing processes if the concentration of caustic alkali in the aqueous vat dye liquor is increased to a marked degree.

In accordance with the invention we provide a process for continuous dyeing of vegetable fibrous material with 120 (one hundred and twenty) grammes per litre and V 400 (four hundred) grammes per litre.

' A preferred concentration is of the order of 200 (two hundred) grammes per litre, and it has been found that this leads to a fifty percent reduction in dyestuff costs with some dyestuffs. Thus the total consumption of dye utilising the process according to the invention is much less for a given quantity of material and the same shade, than with the hitherto normal method of dyeing, as a given amount of dyestutf gives a greater colour value in the relatively short time available in a continuous dyeing process. Thus material dyed by the hitherto normal process will contain considerably more dyestuff than the same material dyed to the same shade under the process of the invention.

The strength of the caustic alkali may be varied with different vegetable fibres, while caustic soda may be used or may be Wholly or partly replaced by caustic potash, sodium zincate, or other alkaline substances known to have a swelling action on cellulose fibres.

Vat dyestuffs which have been found suitable for the process include inter alia:

Caledon Yellow GNS (I. C. I.) (C. I. lll8)-Flavanthrone,

Caledon Direct Black G. S. (I. C. L).

Caledon Gold Orange 368 (I. C. 1.).

Caledon Red BNS (I. C. I.) (C. I. 1162) 1, 2 anthraquinonenaphthacridone.

Paradone Bordeaux RR (L. B. Holliday).

Caledon Olive Green BS I. C. 1.).

Caledon Green 7G5 (l. C. 1.).

2,827,357 Patented Mar. 18, 1958 ice Caledon Oliver RS (I. C. I.) (C. I. ll50)obtained by treating 4:4'-dibenzoylamiuo-1:1 dianthrimide with sulphuric acid.

Caledon Brown RS (I. C. I.) (C. I. 1l51)obtained by treating 4:5 dibenzoylamino-1:1 dianthrimide with sulphuric acid.

Caledon Dark Brown 6R5 (I. C. 1.).

Caledon Brown GS (I. C. I.) (C. I. 1152)a mixture of Caledon'Olive RS and Caledon Brown RS above.

Caledon Brown BS (I. C. I.) (C. I. 1120).

Caledon Brill. Violet RS (I. C. I.) (C. I. 1135).

Caledon Yellow Brown 3G5 (I. C. I.).

A continuous process may advantageously be used in accordance with our British Patents 620,584, 661,086, 681,983, 665,454. and 663,066, which utilise hot molten metal to apply heat and squeezing action on textile material during its continuous passage therethrough. Other continuous vat dyeing processes may, of course, be utilised in some of which steam or hot oil may replace the molten metal as the dye-fixing medium.

The followingspecific examples are now referred to:

Example 1 Dry, unscoured 4 Condenser cotton yarn in tape form is heated to a temperature of 79 to 80 C. by passing over steam heated cylinders and is then passed into an aqueous dye liquor of small volume which floats on the surface of a molten metal bath and which has the following composition:

120 grms. per litre Caledon Dark Brown 6RS (Imperial Chemical Industries).

15 grms. per litre Caledon Yellow GNS-Flavanthrone (Imperial Chemical Industries) (Colour Index 1118).

20 grms. per litre Caledon Direct Black GS (Imperial Chemical Industries).

200 grms. per litre Caustic Soda.

31 grms. per litre Sodium Hydrosulphite.

l5 grms. per litre Glucose Syrup.

2O grms. per litre Alcopol T (Allied Colloids) (Wetting and dispersing agent).

10 grms. per litre Dilford Special (Wetting agent) (Dilford Products). v

The yarn passes continuously through the aqueous dye liquor and through the molten metal bath at a speed of 20 yards per minute giving an immersion time of 0.96 second for the dye liquor and 10.4 seconds for the molten metal. The molten metal is an alloy of Bismuth, Lead, Tin and Cadmium, with a melting point of 71 C., and is maintained at C. The aqueous dye liquor is made up and stored at room temperature and is pumped to the surface of the molten metal through a heater which raises the temperature to 75 C. The volume of dye liquor floating on the surface of the metal is automatically maintained constant. The yarn leaves the molten metal through a 10% solution of Glaubers salt which floats on the exit surface and has a temperature of 90 C., and then passes through the common form of continuous after treatment range where it is oxidised, soaped and rinsed in known manner. The yarn so treated is coloured a nigger brown and is very considerably darker than yarn dyed in a hitherto normal dyebath which in this example would contain 24 grms. of caustic soda per litre.

Example 2 Dry, unscoured, 2/ 32 cotton yarn in tape form is dyed in the manner described in Example 1 but using the following aqueous dye liquor:

grms. per litre Caledon Red BNS1,2 anthraquinonenaphthacridone (Colour Index 1162). 200 grms. per litre Caustic Soda.

i 3 20 grms. p er litre, Sodium Hydrosulp te- 10 grms. per litre Glucose Syrup. 2.0 grms. per litre Alcopol T. lO grms'. per litre Dilfo'rd Special;

The red coloured yarn which results is "about 50% darker than that resultingfrom the use of-hitherto normal quantities of caustic soda which in this examplejwo'uld be 15 grms. per litre; it

Example 3 Dry, scoured cotton drill fabric is dyed in a manner similar to'the yarn of Example 1 but the fabric speed is 40 yards per minute and the aqueous dye liquor-has the following composition:

100 grms. per litre Caledon Gold Orange 3 GS '(Imperial Chemical Industries) (Colour Index).

200 grms. per litre Caustic Soda.

20 grms. per litre Sodium Hydrosulphite.

l grms. per litre Glucose Syrup.

ZO-grms. per litre-Alcopol T.

IOgrms. per litre 'Dilford Special.

The resultant gold coloured fabric isabout 25% darker than a similar dyeing using 15 grms. caustic soda per litre, which is the hitherto'normal quantity.

Example 4 'Dry, scoured, cotton .drill fabric is dyed in a similar manner to Example 3, but using the following aqueous dye liquor: v

IOOIgrms. per litre Caledon Brown RS (C. I. 1151). 200 grms. per litre Caustic Soda.

20tgrms. per litre Sodium Hydrosulphite.

l0 grms. per litre Glucose Syrup.

l0 grms. per-litre Saponified Castor .Oil (wetting agent).

. Example 5 The process of Example 4 is repeated but the 200 grms. per litre caustic soda is replaced by400 grms. per litre caustic potash 7 Example 6 1-00. grms. per litre CaledonRed BNS (C; I. 1162).

5 grms. per litre Saponified Castor Oil (wetting agent). 20. grms. per-litre Sodium Hydrosulphite. I

10 grms. per litre Glucose Syrup.

ligrms, per litre Caustic Soda. v

liquor is dyed a fast-tred'colourlwhich is about 50% darker than that obtained with abath of normal alkalinity.

Asiaforesaid 'the'process is applicable. to other vegetable.

fibres; for example,bleachedlinemfabriccan, with 'advantage, be dyed by the method of Example 3.

We claim: 1

1. A process of molten metal bath dyeing of vegetable fibrous material with vat.dyes,:comprising continuously passing the fibrous material throughhot aqueous dye liquor containinga vatdye and an alkali metal hydro; sulfite floating on the surface of said bath, said aqueous i dyeliquor.containingabout 120 to -400-grams-'per"liter V in=:an amount of 20- to 31 grams per liter.

of caustic alkali. 2..-A process according to claim 1 wherein the" alkali metal hydrosulfite is sodium -hydrosulfite.

' 3. A process accordingto claim 1' wherein the causti alkaliteoncentration is about 200' grams per liter.

4. Aprocess according to claim 1 in which the aqueous dye liquor contains sodium zincate.

F5. Aproeess according toclaim 1 wherein the dye bath also contains glucose.

-6. 1 A: process according to claim lwherein the caustic alkali comprises caustic 'soda. 1 7. 'A process according to claim 6 wherein thealkali metal hydrosulfite is sodium hydrosulfite and is 8. A process according to claim 7 wherein the dye bath contains 10 :to 15 grams per liter of glucose.

9 A process according to claim -8 wherein the caustic soda is present in an amount of about 200 grams per liter.

References Cited in the file of this patent FOREIGN PATENTS 99,337 Germany Sept..l3,.1898

OTHER REFERENCES l'IourJ'Soc. Dyers & Col. for December 1951, pages Jour. Soe. Dyers "& Col. for July 2, pages 249 256.

present a 

1. A PROCESS OF MOLTEN METAL BATH DYEING OF VEGETABLE FIBROUS MATERIAL WITH VAT DYES, COMPRISING CONTINUOUSLY PASSING THE FIBROUS MATERIAL THROUGH HOT AQUEOUS DYE LIQUOR CONTAINING A VAT DYE AND AN ALKALI METAL HYDROSULFITE FLOATING ON THE SURFACE OF SAID BATH, SAID AQUEOUS DYE LIQUOR CONTAINING ABOUT 120 TO 400 GRAMS PER LITER OF CAUSTIC ALKALI. 